Disc storage systems are well known in the art and are used to store information for later retrieval. Such disc storage systems include a rotating disc which carries information thereon and a transducing head positioned over a surface of the disc while the disc rotates at high speed. The head is carried on a slider which is designed to “fly” just over the surface of the recording disc. The head may be used to write information onto the disc and/or read information from the disc. While such systems have become increasingly sophisticated, the problems with increased storage density have become more difficult to solve. Specifically, one of the problems is called the superparamagnetic limit, which may be generally characterized by the fact that as bits shrink in size, their long-term stability at system temperature diminishes. This means that recorded information will degrade over time, and in the worst case, will self-erase. To combat this tendency, the coercivity of magnetic media must be increased. This makes the recording process more difficult since magnetic heads have limited magnetic field output. As a potential solution to this problem, a technology called thermally-assisted recording is receiving attention. In this system, writing is accomplished via magnetic field modulation over a magnetic medium with vertical magnetization, and a coercivity that is decreased by local heating. The local heating may be applied via a standard magneto-optical (MO) head. (H. Saga, H. Nemoto, H. Sukeda, and M. Takahasi, “A New Recording Method Combining Thermo-Magnetic Writing and Flux Detection,” paper Pd-08 ISOM '98; H. Nemoto, H. Saga, H. Sukeda, and M. Takahashi, “Exchange-Coupled Magnetic Bilayer Media for Thermomagnetic Writing and Flux Detection,” paper Pd-09 ISOM '98; and S. R. Cumpson, P. Hidding, and R. Coehoorn, “A Hybrid Recording Method Using Thermally Assisted Writing and Flux Sensitive Detection,” IEEE Trans. Magn., 2000 incorporated herein by reference.) By incorporating a GMR (giant magnetoresistive) read sensor into the transducing head, system advantages in signal-to-noise ratio (SNR) and resolution (signal roll off with feature size) can be achieved. The medium can be separately optimized for writing and reading if a dual magnetic layer structure is employed, including a memory layer for data storage and a read layer for readback. The reading process comprises heating the media in the region to be read to a temperature such that the read layer replicates the domain structure of an underlying write (memory) layer on the disc of the addressed data track. The room temperature coercivity of the read layer is chosen so that it is not affected by the write layer, but is switched by the bias magnet. The two layer medium may be composed of a high coercivity MO-like (ferrimagnetic) layer and an intermediate coercivity (ferromagnetic) read layer. The read layer is heated by the read optical beam, thereby replicating the magnetization contained in the write layer to be read only across the track of interest, which may be less than the width of the GMR sensor. Obviously, in a system such as this, optimizing the properties of the disc to be used is essential. It is especially important to optimize the thermal properties of the disc for reading and writing.